Two-dimensional second-order spatial differentiation metasurfaces with different numerical apertures(NAs)were designed by the spatial-frequency Trust-Region algorithm,which can be directly embedded into existing optic...Two-dimensional second-order spatial differentiation metasurfaces with different numerical apertures(NAs)were designed by the spatial-frequency Trust-Region algorithm,which can be directly embedded into existing optical imaging systems to efficiently extract edge information of the observed targets.The spatial-frequency Trust-Region algorithm was implemented by integrating the Fourier modal method(FMM)with the Trust-Region algorithm to perform inverse optimization of the metasurface nanostructure.The fabricated metasurface with high-resolution functionality achieved a resolution of 1.2μm and numerical aperture of 0.87,while the high-contrast one obtained a root-mean-square(RMS)contrast higher than that of the first with a numerical aperture of 0.26.Embedded in an optical microscope,the high-resolution differentiation metasurface,with more high-spatial-frequency components in the transfer function,was utilized to extract fine structures of unstained,even transparent,cell images,providing a new avenue for image segmentation,such as in magnetic resonance imaging.The high-contrast counterpart,due to its high transmission efficiency,was employed to detect edges in dynamic images of paramecia and Brachionus without motion smear,offering potential for application in microsurgical procedures involving real-time image analysis.展开更多
基金National Natural Science Foundation of China(61927822)。
文摘Two-dimensional second-order spatial differentiation metasurfaces with different numerical apertures(NAs)were designed by the spatial-frequency Trust-Region algorithm,which can be directly embedded into existing optical imaging systems to efficiently extract edge information of the observed targets.The spatial-frequency Trust-Region algorithm was implemented by integrating the Fourier modal method(FMM)with the Trust-Region algorithm to perform inverse optimization of the metasurface nanostructure.The fabricated metasurface with high-resolution functionality achieved a resolution of 1.2μm and numerical aperture of 0.87,while the high-contrast one obtained a root-mean-square(RMS)contrast higher than that of the first with a numerical aperture of 0.26.Embedded in an optical microscope,the high-resolution differentiation metasurface,with more high-spatial-frequency components in the transfer function,was utilized to extract fine structures of unstained,even transparent,cell images,providing a new avenue for image segmentation,such as in magnetic resonance imaging.The high-contrast counterpart,due to its high transmission efficiency,was employed to detect edges in dynamic images of paramecia and Brachionus without motion smear,offering potential for application in microsurgical procedures involving real-time image analysis.
